The present invention relates to a mouldable photographic material and a method of forming same, particularly, although not exclusively for decorative use.
Conventional photographic material lacks stability when subjected to heat. Consequently, such material is unsuitable for use in moulding processes and other environments where it might be subject to thermal and other forms of environmental stress. The desirability of a photographic material which is capable of being formed into for example the trim components of a vehicle or the housing of a consumer electrical item is clear. Consequently, there have been many attempts to obtain a suitable mouldable photographic material. An early example of such an attempt is shown in French Patent No. 968.638 which relates to a method for the preparation of photographic surface for moulding and also U.K. Patent No. 739,477 relating to photographic silver halide films. However, none of the attempted solutions to date has achieved a satisfactory solution free from defects in appearance particularly cracking of the image and heat induced distortion.
It is therefore an object of the present invention to provide a photographic material and method for producing same which material is capable of being moulded under conditions of heat and/or pressure without suffering the degradation in quality and finish shown exhibited by the prior art. It is a further object of the present invention to provide such a material which may be produced without the need for specialised equipment.
According to the present invention, there is provided a method of forming a three-dimensional photographic material article, comprising the steps of coating a thermoplastic base with, in order, a primer layer, and a light sensitive layer and then, following exposure, developing, and drying steps bonding a protective thermoplastic foil to the exposed and developed light sensitive layer prior to moulding the material.
Whilst the material may be provided for subsequent processing in individual sheet form advantageously the material could be prepared in roll form thereby enabling the product to be used in a continuous production process.
The thermoplastic base is preferably formed from a PVC material although a polycarbonate can be equally effective particularly where the physical characteristics of polycarbonate provide advantages in terms of the final moulded product. Alternatively, acrylonitrile butadiene styrene (ABS) may be used as the base, either on its own or with a polyvinylchloride (PVC). In any case, the material is preferably pigmented to form an opaque white which ensures accurate rendition of colour in the exposed light sensitive layer. The thermoplastic foil may be formed of any suitable material exhibiting the desired physical properties, e.g. scratch resistance. Accordingly, polyester and polycarbonate foils have been found to be particularly effective.
Where a PVC material is used as the base, an additional compound to prevent plasticiser migration may be included in the primer layer or, indeed applied as a separate layer. Similarly, a compound to prevent water migration may be included where the base is a polycarbonate material. Further adhesive layers and the like may be added to both sides of the material, i.e. the uncoated side of the base and the protective foil depending on the particular application of the material.